Fugitive emissions
Section 8.3.1.1 – Valves
Valves are typically the most common component found within the LDAR program and consist of the most leaks . The monitor will be directed to place the probe tip on the leaking interface of the packing and stem area . It is important to test the complete circumference of these areas . Once they have monitored both of these areas they will turn their attention to monitoring the bonnet flange area , if it is not wrapped in insulation .
Figure 4 . Figure 5 . Figure 6 .
8.3.1.1 - Valves . The most common source of leaks from valves is the seal between the stem and housing . Place the probe at the interface where the stem exits the packing gland and sample the stem circumference . Also , place the probe at the interface of the packing gland take-up flange seat and sample the periphery . In addition , survey valve housings of multipart assembly at the surface of all interfaces where a leak could occur .
Section 8.3.1.2 - Flanges and Other Connections
Flanges and ‘ other ’ connection component directions can be found in 8.3.1.2 . For these applications the monitoring personnel will be instructed to place the probe tip at the interface of the joint / connection and monitor the circumference .
8.3.1.2 - Flanges and Other Connections . For welded flanges , place the probe at the outer edge of the flange gasket interface and sample the circumference of the flange . Sample other types of nonpermanent joints ( such as threaded connections ) with a similar traverse .
Section 8.3.1.3 – Pumps and Compressors
Pumps and compressors will have multiple areas in which a potential leak can be found . If any moving parts are observed , the monitoring personnel is allowed to let the tip of the probe float at most 1cm from that part . For all the other areas , place the probe tip on the leak interfaces and traverse the circumference .
8.3.1.3 - Pumps and Compressors . Conduct a circumferential traverse at the outer surface of the pump or compressor shaft and seal interface . If the source is a rotating shaft , position the probe inlet within 1 cm of the shaftseal interface for the survey . If the housing configuration prevents a complete traverse of the shaft periphery , sample all accessible portions . Sample all other joints on the pump or compressor housing where leakage could occur .
Section 8.3.1.4 - Pressure Relief Devices
For Pressure Relief devices that vent into the atmosphere , as shown in Figure 9 , the probe tip should be placed at the center of the ‘ horn .’ If the ‘ horn ’ is out of reach , the ‘ weep ’ hole ( noted by the green arrow in Figure 9 ) is the best alternate . 8.3.1.4 provides a little more detail on interfaces , but overall , these two locations are going to be the main areas to review .
8.3.1.4 - Pressure Relief Devices . The configuration of most pressure relief devices prevents sampling at the sealing seat interface . For those devices equipped with an enclosed extension , or horn , place the probe inlet at approximately the center of the exhaust area to the atmosphere .
Section 8.3.1.5 – Process Drains
For Process drains , the monitoring location is at the center of the opening to the atmosphere .
If the drain is covered then it is important to monitor the circumference of the drain covering .
8.3.1.5 - Process Drains . For open drains , place the probe inlet at approximately the center of the area open to the atmosphere . For covered drains , place the probe at the surface of the cover interface and conduct a peripheral traverse .
Section 8.3.1.6 Open-ended Lines or Valves
For open-ended lines or valves in 8.3.1.6 , the probe tip should be placed in the center of the opened area . Do not pass the plane of the opened area though when monitoring .
8.3.1.6 Open-ended Lines or Valves . Place the probe inlet at approximately the center of the opening to the atmosphere .
Section 8.3.3.1 and 8.3.3.2 – Alternate Screening Procedure
For alternate methods of testing refer to sections 8.3.3 of Method 21 . This section provides insight into the soap solution method which uses the appearance of bubbles as the solution is placed onto the component to indicate a leak . While this method is not used in a day-to-day LDAR world , it is used by maintenance and operations personnel if a re-monitoring technician is not available .
8.3.3.1 A screening procedure based on the formation of bubbles in a soap solution that is sprayed on a potential leak source may be used for those sources that do not have continuously moving parts , that do not have surface temperatures greater than the boiling point or less than the freezing point of the soap solution , that do not have open areas to the atmosphere that the soap solution cannot bridge , or that do not exhibit evidence of liquid leakage . Sources that have these conditions present must be surveyed using the instrument technique of section 8.3.1 or 8.3.2
Figure 7 . Figure 8 . Figure 9 .
8.3.3.2 Spray a soap solution over all potential leak sources . The soap solution may be a
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